Hi,
the 500 line limit is when Mach3 is in Demo mode or unlicensed, its got nothing to do with the UC100.
There are dozens of fake Chinese made UC100's, and they are not a patch on the real thing.....but its also possible that those same Chinese manufacturers will 'give' you a
pirate copy of Mach3 which does not not the 500 line limit....ie pirate.
The UC100 has the equivalent of one parallel port of output, ie 17 IO's. Enough for the most basic of machines only.
A UC400 has two ports (34 IO's), an Ethernet SmoothStepper has three ports (51 IO's) and a UC300 has five ports (85 IO's), and
these are more suitable for future expansion.
Craig